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Wyszukujesz frazę "test model" wg kryterium: Temat


Tytuł:
Experimental analysis of the helicopter ditching
Autorzy:
Kraskowski, Marek
Powiązania:
https://bibliotekanauki.pl/articles/1810600.pdf
Data publikacji:
2020
Wydawca:
Akademia Marynarki Wojennej. Wydział Dowodzenia i Operacji Morskich
Tematy:
rotorcraft
helicopter
ditching
scale model test
Opis:
The paper presents the method and results of the model tests of helicopter ditching, aimed at adaptation of the helicopter's construction for marine mis-sions. The experiment, realized by Maritime Advanced Research Centre S.A. (CTO) required elaboration of dedicated measurement stand, and solving a number of specific technical problems resulting from the necessity of assuring the repeatability, and required accuracy of the measurements and scalability of the results. Such kind of experiment is not a standard task of a hydrodynamic model testing institution, so it brings an innovation in the testing methodology. The paper presents the details of the test stand and the model itself with rotating rotor, design of the experiment, as well as an overview of the results and main conclusions.
Źródło:
Rocznik Bezpieczeństwa Morskiego; 2020, R. XIV; 205--219
1898-3189
Pojawia się w:
Rocznik Bezpieczeństwa Morskiego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental evaluation of forward speed effect on maneuvering hydrodynamic derivatives of a planing hull
Autorzy:
Kazerooni, M. F.
Seif, M. S.
Powiązania:
https://bibliotekanauki.pl/articles/135366.pdf
Data publikacji:
2017
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
planing hull
maneuvering
model test
derivative
hydrodynamic
Opis:
The calculation of unknown hydrodynamic derivatives of the equations of motion is the first step to estimate ship maneuverability and dynamic stability. These derivatives can be obtained theoretically, experimentally and numerically. Despite the development of the oblique towing model test to measure the hydrodynamic derivatives of displacement ships, limited experimental results are available for hydrodynamic derivatives of high speed crafts and speed dependency of the hydrodynamic derivatives is not understood well. In this paper a systematic series of model tests is described to determine the effect of forward speed on hydrodynamic derivatives of a monohull planing craft and the variations of the hydrodynamic derivatives by forward speed are derived. According to the results, hydrodynamic derivatives of planing hull are dramatically changed by variations of forward speed. Moreover, it is not possible to introduce a constant hydrodynamic derivative in the all the ranges of drift angle. Thus, the method of known constant hydrodynamic derivatives is not applicable to the simulation of planing craft maneuvering and variable hydrodynamic derivatives should be applied.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2017, 49 (121); 40-53
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Test studies of the resistance and seakeeping performance of a trimaran planing hull
Autorzy:
Ma, W.
Sun, H.
Zou, J.
Zhuang, J.
Powiązania:
https://bibliotekanauki.pl/articles/259495.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
trimaran planing hull
appendix
resistance
seakeeping
model test
Opis:
Towing tank tests in calm water were performed on a trimaran planing hull to verify its navigational properties with different displacements and centres of gravity, as well as to assess the effects of air jets and bilge keels on the hull’s planing capabilities, and to increase the longitudinal stability of the hull. Hydrostatic roll tests, zero speed tests, and sea trials in the presence of regular waves were conducted to investigate the hull’s seakeeping ability. The test results indicate that the influence of the location of the centre of gravity on the hull resistance is similar to that of a normal trimaran planing hull; namely, moving the centre of gravity backward will reduce the resistance but lower the stability. Bilge keels improve the longitudinal stability but slightly affect the resistance, and the presence of air jets in the hull’s channels decreases the trim angle and increases heaving but has little effect on the resistance. Frequent small-angle rolling occurs in waves. The heaving and pitching motions peak at the encounter frequency of , and the peaks increase with velocity and move towards greater encounter frequencies. When the encounter frequency exceeds, the hull motion decreases, which leads to changes in the navigation speed and frequency.
Źródło:
Polish Maritime Research; 2015, 1; 22-27
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effective width rule in the analysis of footing on reinforced sand slope
Autorzy:
Abdi, Abdelmadjid
Abbeche, Khelifa
Athmania, Djamel
Bouassida, Mounir
Powiązania:
https://bibliotekanauki.pl/articles/178217.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bearing capacity
eccentricity
footing
geogrid
model test
slope
Opis:
This paper presents the results obtained from an experimental programme and numerical investigations conducted on model tests of strip footing resting on reinforced and unreinforced sand slopes. The study focused on the determination of ultimate bearing capacity of strip footing subjected to eccentric load located either towards or opposite to the slope facing. Strip footing models were tested under different eccentricities of vertical load. The obtained results from tests conducted on unreinforced sand slope showed that the increase in eccentricity of applied load towards the slope facing decreases the ultimate bearing capacity of footing. Predictions of the ultimate bearing capacity obtained by the effective width rule are in good agreement with those proposed from the consideration of total width of footing subjected to eccentric load. The ultimate bearing capacity of an eccentrically loaded footing on a reinforced sand slope can be derived from that of axially loaded footing resting on horizontal sand ground when adopting the effective width rule and the coefficient of reduction due to the slope. When increasing the distance between the footing border to the slope crest, for unreinforced and reinforced ground slope by geogrids, the ultimate bearing capacity of footing is no more affected by the slope ground.
Źródło:
Studia Geotechnica et Mechanica; 2019, 41, 1; 42-55
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model tests on characteristic of suction caissons in saturated fine sand under intermittent loading
Autorzy:
Shi, P.
Powiązania:
https://bibliotekanauki.pl/articles/258534.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
intermittent suction installation
model test
sand
suction caisson
Opis:
Suction caissons are often used for the caissons of both offshore oil platforms and offshore wind power projects because of their advantages of simple construction, economical cost, and reusability. In this study, model tests were conducted in sand in order to investigate the effects of the caisson installation method on the penetration depth and the critical suction. Results of the test program showed that the method of changing the frequency of suction during different stages of the process can increase the penetration depth of the caisson. Combining with the deformation of the soil body inside and outside the caisson, the existing method for calculating the critical suction is modified, and the critical suction calculation equation of the discontinuous penetration test is proposed. Based on the test results, the calculation equation of the soil heave height can be more accurate predicted. The analysis results verify that the calculation method and the actual results are in good agreement.
Źródło:
Polish Maritime Research; 2018, S 3; 127-135
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and experimental study on seakeeping performance of a high-speed trimaran with T-foil in head waves
Autorzy:
Li, Ang
Li, Yunbo
Powiązania:
https://bibliotekanauki.pl/articles/258842.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
trimaran
T-foil
URANS
longitudinal motion
model test
Opis:
The longitudinal motion characteristics of a slender trimaran equipped with and without a T-foil near the bow are investigated by experimental and numerical methods. Computational fluid dynamics ( CFD) method is used in this study. The seakeeping characteristics such as heave, pitch and vertical acceleration in head regular waves are analyzed in various wave conditions. Numerical simulations have been validated by comparisons with experimental tests. The influence of large wave amplitudes and size of T-foil on the longitudinal motion of trimaran are analyzed. The present systematic study demonstrates that the numerical results are in a reasonable agreement with the experimental data. The research implied that the longitudinal motion response values are greatly reduced with the use of T-foil.
Źródło:
Polish Maritime Research; 2019, 3; 65-77
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model investigation of piston ring-cylinder liner collaboration on a high power engine
Autorzy:
Serdecki, W.
Krzymień, P.
Powiązania:
https://bibliotekanauki.pl/articles/245364.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
marine combustion engine
piston ring
oil film
model test
Opis:
Failures caused by improper collaboration between piston ring and cylinder liner still happen on engines ofhigh output, marine ones in particular. Among causes of this phenomenon one can mention higher mechanical and thermal loads of crank mechanism as well as difficulties in supply and distribution of lubricating oil over the entire surface of cylinder liner. It would be extremely difficult and because of regulations in most cases impossible to perform tests on correct collaboration between rings and liner of real running engine and on the other hand such tests on a test stand would be quite expensive. Use of mathematical models and tests on simulation model stands offers a way to reduce these costs. Basic dependences connecting piston ring geometry with oil film parameters and introductory results of computations performed with the use of analytical model of test stand will be presented in this paper. The tests are to be carried out for ring geometry corresponding to that of marine engine rings. Due to that, using presented earlier formulas and computer program constructed by the authors the phenomena accompanying operation of different versions of rings were analyzed from the point of oil film thickness and generated friction losses. These ring versions which revealed the most advantageous properties will be made and tested on a test stand.
Źródło:
Journal of KONES; 2009, 16, 4; 407-413
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of ventilation to limit airborne infection concentration in an isolation room
Autorzy:
Kassem, Fatma A.-M.
Abdelgawad, Ahmed Farouk
Abu El-Ezz, A. E.
Nassief, Mofreh M.
Adel, Mohamed
Powiązania:
https://bibliotekanauki.pl/articles/24201035.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
COVID-19
ventilation
exhaled air
air exchange
test model
hospital room
CO2
wentylacja
powietrze wydychane
sala szpitalna
wymiana powietrza
model badawczy
Opis:
Coronavirus (COVID-19) was detected at the end of 2019 and has since caused a worldwide pandemic. This virus is transferred airborne. In this study, an investigation was carried out of the ventilation strategies inside the isolation room based on exhaust air locations. To reduce the infection disease (COVID-19), due to the spreading of exhaled contaminants by humans in interior environments, five models for ventilation systems differing in the position of the outlet and inlet were used. This study aims to increase knowledge regarding the exhaled contaminant distribution under different environ-mental conditions (opening exhaust and negative pressure). The results showed a good agreement be-tween the computational results and the experimental data. Tracer gas CO2 was used to evaluate the air quality experimentally and computationally. The results showed that stable conditions are obtained inside the room at a negative pressure value above –1.5 Pa. The residence time of the infected airborne decreases when the pressure difference increases. The study revealed that the model with an air outlet opening installed behind the patient enabled avoiding the spread of infection in the room.
Źródło:
Environment Protection Engineering; 2023, 49, 2; 39--54
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Motion prediction of catamaran with a semisubmersible bow in wave
Autorzy:
Sun, H.
Jing, F.
Jiang, Y.
Zou, J.
Zhuang, J.
Ma, W.
Powiązania:
https://bibliotekanauki.pl/articles/258596.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
SSB catamaran
model test
overset grid
motion region
motion response
Opis:
Compared with standard vessels, a slender catamaran with a semi-submerged bow (SSB) demonstrates superior seakeeping performance. To predict the motion of an SSB catamaran, computational fluid dynamics methods are adopted in this study and results are validated through small-scale model tests. The pitch, heave, and vertical acceleration are calculated at various wavelengths and speeds. Based on the overset grid and motion region methods, this study obtains the motion responses of an SSB catamaran in regular head waves. The results of the numerical studies are validated with the experimental data and show that the overset grid method is more accurate in predicting the motion of an SSB catamaran; the errors can be controlled within 20%. The movement data in regular waves shows that at a constant speed, the motion response initially increases and then decreases with increasing wavelength. This motion response peak is due to the encountering frequency being close to the natural frequency. Under identical sea conditions, the motion response increases with the increasing Froude number. The motion prediction results, that derive from a shortterm irregular sea state, show that there is an optimal speed range that can effectively reduce the amplitude of motion.
Źródło:
Polish Maritime Research; 2016, 1; 37-44
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods of investigation of road vehicles in context of immunity to electromagnetic field
Autorzy:
Łukjanow, S.
Tokarzewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/245510.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
road vehicles
EMC immunity tests
open-area partially shielded test site model
Opis:
The question of testing of vehicles and their subassemblies, especially in the range of electrical and electronic equipment, is very extensive. The scope of the relevant tests becomes wider and the requirements, especially in the range of safety, reliability and comfort, become higher. Of particular significance, are in recent years, tests concerning electromagnetic compatibility (EMC) of whole vehicles and their subassemblies. A survey of basic standardized EMC test methods is presented in the paper. Moreover, an alternative test method of vehicle immunity worked out by authors is proposed. The method has been verified by using the open-area partially shielded test site (OAPSTS) model and compared with standardized methods contained in ECE UN Regulation No. 10 and EU Directive 2004/104/EC. Tests of vehicle immunity to electromagnetic field have been performed using the model of OAPSTS and the vehicles: Citroen-Berlingo, Skoda-Octavia and Daewoo-Lanos. Estimation of basic statistical parameters has also been worked out. The obtained results show that the proposed method is reliable and, on the other hand, it is more accessible and less expensive than the standardized methods in which employing of very expensive absorber-lined shielded test chambers is necessary. The present paper extends the results obtained in [6, 7].
Źródło:
Journal of KONES; 2011, 18, 3; 211-217
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł

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